Articles molded of polycarbonate are well known. The utility and method for making colored articles that are prepared from pigmented polycarbonate compositions are well known. Also known are processes for dyeing articles molded of resins, including polycarbonates, and including lenses that have been tinted by immersion in special pigmenting mixtures. Among the advantages attained by such tinting of lenses, mention has been made of reduced light transmission and mitigation of glare.
U.S. Pat. No. 4,076,496 disclosed a dye bath composition suitable for dyeing hard-coated polarized lenses; the composition of the bath included a dye and as a solvent, a mixture of glycerol and ethylene glycol, optionally with a minor proportion of water or other organic solvent.
U.S. Pat. No. 5,453,100 disclosed polycarbonate materials that are dyed by immersion into a mixture of dye or pigment dissolved in a solvent blend. The blend is made up of an impregnating solvent that attacks the polycarbonate and allows the impregnation of the dye or pigment and a moderating solvent that mitigates the attack of the impregnating solvent. The impregnating solvent thus disclosed includes at least one solvent selected from dipropylene glycol monomethyl ether, tripropylene glycol monomethyl ether and propylene glycol monomethyl ether. PCT/CA99/00803 (WO 0014325) disclosed tinting plastic articles by immersion in an aqueous dispersion and exposing the dispersion and immersed article to microwave radiation. JP 53035831 B4 disclosed polycarbonate moldings that are dyed in aqueous dispersion containing dispersed dyes and diallyl phthalate, o-phenylphenol or benzylalcohol. Also, JP 55017156 disclosed aliphatic polycarbonate lenses that are colored with a liquor containing dyes and water. JP 56031085 (JP-104863) disclosed compositions containing a disperse dye in an aliphatic ketone and polyhydric alcohol said to be useful in coloring polycarbonate films at room temperature. JP2000248476 disclosed a molded polycarbonate bolt that was dyed with a solution containing dyes, an anionic leveling agent and then treated with a solution containing thiourea dioxide.
U.S. Pat. No. 4,812,142 disclosed polycarbonate articles dyed at a temperature of 200° F. or above in a dye solvent having a boiling point of at least 350° F., and U.S. Pat. No. 3,514,246 disclosed immersing molded polycarbonate articles in an emulsified dye liquor which contains a water insoluble dyestuff, an oil-soluble surface active agent dissolved in an aliphatic hydrocarbon solvent and water. The procedure was repeated with similar results where the surfactant was replaced by a poly(oxyethylene) derivative. U.S. Pat. No. 3,532,454 disclosed dyeing of polycarbonate fibers with a dye composition that contains at least one of alkoxyalkylbenzyl ether, alkylene glycol di-benzyl ether, benzoic acid alkoxyalkyl ester or phenoxy acetic acid-alkoxyalkyl ester. U.S. Pat. No. 3,630,664 disclosed a dye bath that required the presence of a carbonate conforming to a specific formula, e.g. ethyl-benzyl-carbonate.